Comprehensive Biotechnological Strategies for Podophyllotoxin Production from Plant and Microbial Sources

Podophyllotoxin is derived from plant sources and exhibits strong anticancer activity. However, limited natural availability and environmental impacts from traditional extraction methods drive the search for alternative production approaches. This review explores diverse strategies for sustainable podophyllotoxin synthesis, including biosynthesis, semi-synthesis, and biotransformation. Biosynthetic methods involve metabolic pathway engineering in plant or microbial cells, enabling increased yields by manipulating precursor availability and gene expression. Semi-synthetic approaches modify podophyllotoxin precursors or intermediates to enhance therapeutic effects, with derivatives like etoposide and teniposide showing clinical efficacy. Biotransformation, utilising organisms such as endophytic fungi or human hepatic enzymes, enables the transformation of substrates like deoxypodophyllotoxin into podophyllotoxin or its derivatives, yielding compounds with reduced environmental impact and improved purity. The anticancer efficacy of podophyllotoxin and its derivatives stems from multiple mechanisms. These compounds disrupt cell mitosis by inhibiting microtubule assembly, impairing nucleoside transport, and blocking topoisomerase II activity, leading to DNA cleavage and cancer cell apoptosis. Podophyllotoxin and its derivatives also exhibit anti-angiogenesis and anti-metastatic effects through signalling pathway modulation. Notably, derivatives like deoxypodophyllotoxin utilise advanced delivery systems, enhancing targeted efficacy and reducing side effects. Given the varied mechanisms and growing therapeutic applications, optimising biotransformation and delivery techniques remains essential for advancing podophyllotoxin-based therapies. This comprehensive review underscores the compound's potential as a robust anticancer agent and the need for continued research to maximise its production and clinical effectiveness.

Enhanced podophyllotoxin production of endophyte Fusarium proliferatum TQN5T by host extract and phenylalanine

Fermentation technology using endophytes is considered a potential alternative approach for producing pharmaceutical compounds like podophyllotoxin (PTOX). In this study, fungus TQN5T (VCCM 44284) was selected from endophytic fungi isolated from Dysosma versipellis in Vietnam for PTOX production through TLC. The presence of PTOX in TQN5T was further confirmed by HPLC. Molecular identification indicated TQN5T as Fusarium proliferatum with 99.43% identity. This result was asserted by morphological characteristics such as white cottony, filamentous colony, layer and branched mycelium, and clear hyphae septa. Cytotoxic assay indicated both biomass extract and culture filtrate of TQN5T presented strong cytotoxicity on LU-1 and HepG2 with IC50 of 0.11, 0.20, 0.041, and 0071, respectively, implying anti-cancer compounds were accumulated in the mycelium and secreted into the medium. Further, the production of PTOX in TQN5T was investigated in the fermentation condition supplemented with 10 µg/ml of host plant extract or phenylalanine as elicitors. The results revealed a significantly higher amount of PTOX in the PDB + PE and PDB + PA at all studied time points in comparison with PDB (control). Especially, after 168 h of culture, PTOX content in the PDB with plant extract reached the peak with 314 µg/g DW which is 10% higher than the best yield of PTOX in previous studies, denoting F. proliferatum TQN5T as a promising PTOX producer. This is the first study on enhancing the PTOX production in endophytic fungi by supplementing phenylalanine-a precursor for PTOX biosynthesis in plants into fermented media, suggesting a common PTOX biosynthetic pathway between host plant and endophytes. KEY POINTS: • Fusarium proliferatum TQN5T was proven for PTOX production. • Both mycelia extract and spent broth extract of Fusarium proliferatum TQN5T presented strong cytotoxicity on cancer cell lines LU-1 and HepG2. • The supplementation of 10 µg/ml host plant extract and phenylalanine into fermentation media of F. proliferatum TQN5T improved the yield of PTOX.

Production of the secondary metabolite catechin by in vitro cultures of Camellia sinensis L

Background Catechin is one of the secondary metabolites in Camellia sinensis L. that is alternatively produced through in vitro cultures. The in vitro culture product is possibly improved by optimizing the culture medium with the addition of growth regulators and precursors. The purpose of this study was to confirm the success of the secondary catechin metabolite production through the in vitro culture of C. sinensis L in a relatively short time. Methods The secondary catechin metabolite product is obtained in about 40 days. The study was conducted by (1) leaf cutting for inoculation in Murashige and Skoog media with 1 μg/mL of 2,4-dichlorophenoxyacetic acid growth regulator; (2) the inoculation of callus multiplication on the same medium as a partially modified inoculation media condition with the addition of 1 μg/mL of 6-benzylaminopurine (BAP) and 2 μg/mL of 2,4-dichlorophenoxyacetic acid at concentration; (3) callus multiplication developed on a new medium containing phenylalanine precursors (300 μg/mL); (4) testing growth by harvesting the callus and weighing the wet weight of its biomass and (5) identification of the callus qualitatively and quantitatively by using high-performance liquid chromatography (HPLC). Results The level of secondary catechin metabolite produced was 2.54 μg/mL and 12.13 μg/mL in solid and suspension media, respectively. Conclusions It is concluded that the method is effective and efficient in producing catechin product from C. sinensis L.

Enhanced production of podophyllotoxin, kaempferol, and quercetin from callus culture of Dysosma pleiantha (Hance) Woodson: An endangered medicinal plant

Dysosma pleiantha (Hance) Woodson is one of the endangered traditional Chinese medicinal herbs, highly valued for its medicinal properties by Taiwan's mountain tribes. The present study aims to develop an efficient protocol for callus biomass by optimizing suitable culture medium, carbon source culture condition, and enhanced production of pharmaceutically important podophyllotoxin, kaempferol, and quercetin from callus culture of D. pleiantha under the influence of different additives. Best callus induction was achieved in Gamborg's medium (B5) with 1 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) along with 0.2 mg/L kinetin under dark condition. Tender leaves of D. pleiantha showed the maximum of 86% callus induction among the different explants tested. Highest leaf callus proliferation was noted in B5 medium with 1 mg/L 2,4-D incubated under complete darkness. In addition, it was found that B5 medium with 1 mg/L 2,4-D along with 2 g/L peptone produced more leaf callus biomass and enhanced production of podophyllotoxin (16.3-fold), kaempferol (12.39-fold), and quercetin (5.03-fold) compared to control. Therefore, D. pleiantha callogenesis can provide an alternative source for enhanced production of secondary compounds regardless of the exploitation of its natural plant population.

Effect of Precursor and Phytohormones on Podophyllotoxin Production in Juniperus virginiana Suspension Cultures

Our results showed that cinnamic acid can increase podophyllotoxin production in Juniperus virginiana suspension cultures. The best effect was manifested after a 24-hours application of a 10 mmol/L concentration. The highest podophyllotoxin content was determined at 1.47 mg/g DW and the production was statistically significantly stimulated by about 444% in comparison with the control. Comparison of podophyllotoxin production in the cinnamic acid- and salicylic acid-elicited J. virginiana suspension cultures confirms that the maximum increase in both cases was induced by the 24-hours application of the 10 mmol/L concentration. In contrast, the best effect of jasmonic acid was manifested after the longest 168-hours application of a 5 mmol/L concentration.